Kindergarten · Place Value · MAT-K-PV-002
Compare Teen Numbers
Compare two teen numbers by reasoning about their ones after recognizing each has one ten.
Learning objectives
What you should be able to do
- Compare two teen numbers by reasoning about their ones after recognizing each has one ten.
- Use greater than, less than, and equal language with teen numbers.
- Explain comparisons using base-ten models or number-line position.
Prerequisite check
Make sure the foundation is ready.
Checks place-value structure.
Checks comparison concepts and vocabulary.
Learn
Build the idea from meaning, not memorization.
Teen numbers share the same number of tens
For any two numbers from 11 through 19, each has one ten. Because the tens are equal, the comparison depends on the number of extra ones.
More ones means the greater teen number
Seventeen has one ten and seven ones; fourteen has one ten and four ones. Seven ones are more than four ones, so 17 is greater than 14.
A number line gives another proof
Teen numbers increase from left to right: 11,12,13,...,19. The number farther right is greater.
Equality still means same value
Two copies of the numeral 16 are equal even if one is modeled with blocks and the other with counters. Representation can differ while value remains the same.
Interactive math lab
Change it. See what stays true.
Base-Ten Lab
Change hundreds, tens, and ones and watch the total rebuild from place value.
- build two teens
- compare ones
- select relation
- verify number line
Worked examples
Twenty different ways to see the concept work.
Compare 11 and 12.
11 < 12Both have one ten; 1 one is fewer than 2 ones.
Compare 14 and 13.
14 > 13Four ones are more than three.
Compare 15 and 15.
15 = 15Same ten and same ones.
Compare 17 and 19.
17 < 19Seven ones are fewer than nine.
Compare 18 and 16.
18 > 16Eight ones exceed six.
Which is greater: 12 or 18?
18Both have one ten; eight ones are more than two.
Which is less: 16 or 13?
13Three ones are fewer than six.
Compare 19 and 11.
19 > 11Nine ones exceed one.
Compare 13 and 14 with blocks.
13 < 14Both use one ten; 14 has one extra one.
Compare 18 and 17 with a number line.
18 > 17Eighteen is one step to the right.
Which has more ones: 15 or 12?
15Five ones exceed two.
Which has fewer ones: 11 or 16?
11One one is fewer than six.
Fill 14 __ 18.
<Four ones are fewer than eight.
Fill 19 __ 17.
>Nine ones are more than seven.
Fill 16 __ 16.
=Both values are identical.
If 13 gains one, compare the new number with 13.
14 > 13One extra one makes the number greater.
If 18 loses one, compare the new number with 18.
17 < 18One fewer one makes the number smaller.
Explain 12<19 without counting all objects.
Both have one ten; compare 2 ones with 9 ones.Nine extra ones makes 19 larger.
A model has ten+6; another has ten+4. Compare.
16 > 14The tens match, so compare six and four ones.
Why is teen-number comparison easier after grouping ten?
The equal tens cancel as a comparison issue, leaving only the ones to compare.Place value reduces the problem.
Practice
Guided practice with hints
01Compare 13 and 17.
Hint: Both have one ten; compare extra ones.
Answer: 13<17
02Compare 18 and 12.
Hint: Compare eight ones with two.
Answer: 18>12
03Which is less: 15 or 19?
Hint: Five ones versus nine.
Answer: 15
04Fill 16 __ 14.
Hint: Which has more extra ones?
Answer: 16>14
05Compare ten+3 and ten+3.
Hint: Same tens and ones.
Answer: equal
06Why is 19 the greatest teen number below 20?
Hint: It has one ten and the most possible extra ones before another ten is formed.
Answer: It has nine ones.
Practice
Independent practice
0111 __ 15
Answer: 11<15
0217 __ 14
Answer: 17>14
0318 __ 18
Answer: 18=18
04Which is greater: 13 or 16?
Answer: 16
05Which is less: 19 or 12?
Answer: 12
06Compare ten+5 with ten+8.
Answer: 15<18
07What matters after noticing both teen numbers have one ten?
Answer: Compare the ones.
08Which is farther right: 14 or 18?
Answer: 18
Common mistakes
Learn to catch the error, not just the answer.
The tens are equal, so the ones digit decides the comparison.
Compare place value, not font size.
Treat the ten as equal in both numbers and compare the loose ones.
Applications & challenge
Use the idea beyond a single exercise.
Applications
- Compare two collections already bundled as ten plus loose objects.
- Compare two teen-number scores and explain using tens and ones.
Challenge problems
Which teen numbers are greater than 16 but less than 19?
17 and 18
If two teen numbers have the same ones digit, can they be different between 11 and 19?
No; each has one ten, so matching ones gives the same number.
Explain 18>14 using both place value and number-line reasoning.
Both have one ten, but 8>4 ones; also 18 lies right of 14.
Why does adding one to 19 change the tens structure?
19+1 makes 20, which is two full tens.
Flashcards
Retrieve it from memory.
Flashcards
Card 1 of 6
Game mode
Teen Number Duel
Build two teen numbers, compare their ones, and choose the correct relationship.
Practice
Mastery check
01Compare 12 and 16.
Answer: 12<16
02Compare 18 and 15.
Answer: 18>15
03Compare 14 and 14.
Answer: 14=14
04Why can you focus on the ones when comparing 11–19?
Answer: Each number has one ten.
05Which is greater: 17 or 19?
Answer: 19
06Which is less: 13 or 11?
Answer: 11
07Use blocks to explain 16>12.
Answer: Both have one ten; six loose ones are more than two.
08Use a number line to explain 15<18.
Answer: 15 lies to the left of 18.
Terminology
Words to know
- compare
- Determine whether one value is greater, less, or equal to another.
- tens digit
- The digit that tells how many groups of ten are represented.
- ones digit
- The digit that tells how many single ones are represented.
- magnitude
- The numerical size or value of a number.
Continue learning
Connected concepts
Curriculum references
Standards and instructional references
California Common Core State Standards for Mathematics — Kindergarten Number & Operations in Base Ten / Measurement & Data
Standards progression for teen numbers and direct measurement comparison.